Table 2.

Unloaded R193H and NTG myocyte contractile and Ca²⁺ transient parameters

Sarcomere Shortening Parameters
	Resting SL (um)	Shortening Amplitude (um)	Dep Velocity (%amp)	50% Relaxation Time (s)	75% Relaxation Time (s)	90% Relaxation Time (s)
NTG	1.835±0.008	0.103±0.009	19.69±0.49	0.0689±0.002	0.107±0.004	0.18±0.01
R193H	1.675±0.01*	0.091±0.004	20.85±0.49	0.104±0.004*	0.209±0.008*	0.39±0.015*

Ca2+ Transient Parameters
	Diastolic Ca2+ (360/380)	Ca2+ Amplitude (360/380)	Rise Velocity (%amp)	50% Decay Time (s)	75% Decay Time (s)	90% Decay Time (s)
NTG	1.14+0.02	0.115+0.012	87.7+8.6	0.141+0.004	0.266+0.012	0.42+0.03
R193H	0.09+0.02	0.055+0.004*	105.2+10.5	0.139+0.005	0.250+0.011	0.40+0.02

Departure and Ca²⁺ transient rise velocity is normalized to shortening and Ca²⁺ amplitude. Relaxation and Ca²⁺ decay time is calculated from peak shortening to 50, 75, or 90% of relaxation.

Values are represented as the mean ± SEM,

^*P<0.05 significantly different, t-test, n = 30 myocytes from 5 preparations.

Key: SL=Sarcomere Length, Dep Velocity = sarcomere length shortening velocity, and Rise Velocity = rate of rise of the Ca²⁺ transient.